Rotary kiln for burning cement, magnesite, lime, and the like



Feb. 8 1927.

H. STEHMANN ROTARY KILN Fon BURNING CEMENT, MAGNlzzsI'ra,` mms, AND THELIKE Filed July s, 1925 Patented F eb. 8, l1927.

UNITED STATES PATENT' OFFICE.

HARRY STEHIANN, 0F BERLIN-HOHEHSCHONHAUSEN. GERMANY.

BOTAR' KILN FOB BURNING CEMENT, MAGNESII'E, LIME, AND THB LIKE.

Application tiled July .3, 1925, Serial No. 41,408, and in Germany Kay20, 1922.

When rotary kilns are used for burning cement, magnesi, lime and thelike/too4 favourably infiuenced as the consumption of coal is increased.

This invention has for its object to avoid this inconvenience byintimate] connecting with the revolving tubular k1ln-a device whichensures that, -in totally or partially neglecting the recuperation ofthe heat radiating from the material which has been burned, only theaccurately regulated quantity of air is supplied to the rotary kllnwhich is actually required for the burnmg process. n It has been foundthat heat-economical advantages may be obtained even withoutrecuperation of the heat of the burnt material when the discharge of therotary kiln is closed absolutely airtight and the kiln is worked withthe smallest ssible quantity of air -regulated in accor ance with thematerial to be burned. The new working method may be applied to any kindof rotary kilns even if, owing to insuliicient building height, itshould be impossible to insert a Cil coolingchamber. The invention isbased on these considerations as, according to the invention, the lessimportant advantage of the recuperation of the heat radiating from the'material which has been burned is entirely or partly abandoned and themore important heat-economical advantage is utilized which results fromthe working with accurately regulated minimum quantities of air for theminimum quantities of fuel required for the material to be burned, anyprejudicial excess of air being avoided. Y Y

The rota-ry kiln is equipped, according to the invention with anairtightly-closing discharging device adapted to permit accurateadjustment of the rotary kiln for the admission of the actually requiredminimum quantity of air corresponding to the minimum quantity offuel.The usual means 4maybe provided eventually for the artificial cooling ofthe dischargingdevice. the required minimum quantity of combustion airbeing admitted into the rotary kiln above said discharging device.

l 'An embodiment of the invention is illustrated, by way of example, inthe accompanyin drawmg which shows an improved rotary iln inlongitudinal section.

' Thev rotary kiln a terminates at the discharge end 1n ahead piecev bwhich serves for closing and with which the airti htly lclosingdischarging' device c'isonecte the latter of which may be cooled by airor wa`` ter in an .well known manner. The combustion air is admittedabove the discharg-v ing device into the rotary kiln togetherwith thefuel through the pipe d and the pipe e is used to introduce additionalair which serves to regulate the. air admission to the minimum quantityrequired. It will be noted that .the ypipe e discharges. into the head bwhich has an air-tight connection with the kiln a above the dischargedevices c, but below the discharge or lower end of.. .Y

the rotary portion c of the kiln'. AThis air is heatedby the cementclinker as it falls to the devices c which, as previously de-4 scribed,prevent the passage of a current of air up t rough them when they areopened todischarge their contents. The air lfor both the fuel feedingand the auxiliary combustion air is supplied by blowers or fans f.

I claim: n

A rotary kiln fonburning cement, magnesite and lime, inclu-ding a rotaryinclined body portion, a head at the lower end thereof,an air-tightdischargepdevice directly connected to the lower end of said head and lmeansto admit fue] to said head and body portion, in combination with anair supply .Y pipe arranged in the hea-d to direct a current HARRYSTEHMANN.

